During a typical packaging process, an integrated circuit (“IC”) is mounted inside a plastic mold compound (“package”). Various points on the IC are electrically connected to lead frames circumscribing the package using bond wires. In turn, the lead frames circumscribing the package are electrically connected to an application board, such as a printed circuit board (“PCB”). In this way, multiple electrical connections are established between the IC and the PCB. For example, FIG. 1 shows a side view of an exemplary IC 100 electrically connected to lead frames 102 of a package 104 using bond wires 106. The lead frames 102 are electrically connected to a PCB 108, thereby establishing multiple electrical connections between the IC 100 and the PCB 108.
Mold compounds (i.e., packages) generally are manufactured in mass quantities. More specifically, specially-shaped molds are used to fabricate sheets having multiple mold compounds. These sheets are subjected to a cutting process or singulation process, wherein the individual mold compounds that comprise each sheet are separated from each other. A top view of an exemplary mold sheet 200 is shown in FIG. 2a. The mold sheet 200 comprises a plurality of individual mold compounds (i.e., “unit packages”) 202. FIG. 2b shows a detailed top view of a unit package 202. As previously mentioned, each package 202 is circumscribed by a lead frame 204.
FIG. 2c shows a detailed top view of a design 210 of the lead frame 204. The lead frame design 210 comprises, among other things, multiple spines 212. Each spine 212 is substantially straight (i.e., no considerable bends, curves, or other angles) as shown in the figure. However, various manufacturing process errors often cause the manufactured lead frame 204 spine of FIG. 2b to differ in shape from the spine 212 of the lead frame design 210 in FIG. 2c. FIGS. 3a and 3b illustrate this concept in greater detail than FIGS. 2b and 2c. In particular, FIG. 3a shows a close-up view of the spine 212 of the lead frame design 210. Each lead frame corner 214 of the spine 212 is shown to be at an angle of approximately 90 degrees. However, as illustrated in FIG. 3b, due to manufacturing variations and errors, a manufactured lead frame 204 may result in a spine 300 having lead frame corners 302 that are rounded in shape.
Referring to FIG. 4a, during a singulation process, the manufactured lead frame 204 is sawed or otherwise cut along singulation lines 401 to separate the unit packages 202 of the mold sheet 200 from each other. As shown in FIG. 4b, the singulation process may successfully separate the unit packages 202 by cutting along the singulation lines 401 of FIG. 4a, such that the spine 300 is removed. However, because the lead frame corners 302 are round in shape, many of the leads 304 may have one or more burrs 400. Each burr 400 is simply a portion of the lead 304 to which the burr 400 is attached that was not removed during the singulation process because of the round shape of the lead frame corners 302. In many cases, burrs 400 of adjacent leads 304 may be large enough to physically abut each other, thus forming short circuit pathways 402. Each short circuit pathway 402 provides an electrical connection between adjacent leads 304, thus short circuiting the leads 304 and rendering the unit package 202 comprising the leads 304 useless.